The frequency of Ozone Alerts worldwide is increasing at an alarming rate and the health concerns are quite conclusive with more and more research reports being issued. These Ozone Alerts as announced by the media are actually Smog Alerts. The warnings are that the very old and the very young should avoid going outdoors if the air quality is very poor. Photochemical smog (summer smog) is caused by the action of sunlight on a mixture of hydrocarbons and oxides of nitrogen created mostly by automobile and industrial exhaust emissions. This smog contains secondary pollutants such as ozone. aldehydes and fine particles. Of these “secondary pollutants”, ozone is used as an indicator as it is easily and accurately monitored, and directly proportional to overall smog levels. When we refer to ozone, we are referring only to tropospheric ozone, not to be confused with stratospheric ozone, which forms a layer around the earth, protecting it from the rays of the sun. Tropospheric ozone is produced by the action of light and the chemical bonding of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Thus “SMOG” and “Ozone” alerts have become synonymous. The severity of smog in an urban area is usually assessed by measuring ground-level ozone. Tropospheric ozone (O3) is found as a ground-level polluting gas.
Smog, formed mainly above urban centers, is composed mainly of tropospheric ozone (O3); primary or coarse particulate matter such as soot, pollen and dust; and secondary or fine particulate matter such as sulphur oxides, volatile organic compounds, nitrogen oxides (NOx) and ammonia gas. As described by the EPA, coarse particles are larger than 2.5 micrometer and smaller than 10 micrometers in diameter, and fine particles are thus 2.5 micrometers and smaller.
As a result of heat from the rays of the sun, the concentration of ground-level ozone is highest in urban centers in the summer. Weather conditions also affect ozone formation; masses of stagnant air can hold pollutants at round level for several days.
Many people have resorted to wearing masks to filter out the primary and secondary particulate matter. The masks are needed by those who have already developed respiratory issues due to the smog. Many others don the masks prophylactically. Regardless of the reason for wearing the masks—most people do not realize that the masks are often not sufficient filters. Most face masks are only 20-30% effective (1) because of the inadequate filtration media. There are facemasks known as N95 and N100 that employ a much more effective media but often people are nor wearing the facemasks appropriately which servers to lower the efficacy. Many people are not wearing the appropriate clips and are not aware of the gaps in these face masks that don't properly conform the to the users face.